diff --git a/litelist-app/src/util.ts b/litelist-app/src/util.ts
index e6d5855..fc63eb3 100644
--- a/litelist-app/src/util.ts
+++ b/litelist-app/src/util.ts
@@ -36,7 +36,7 @@ export function getSecondsTilExpire(token: string): number {
  *
  * @return Formatted string.
  */
-export function humanFileSize(bytes, si=false, dp=1) {
+export function humanFileSize(bytes: number, si=false, dp=1) {
     const thresh = si ? 1000 : 1024;
 
     if (Math.abs(bytes) < thresh) {